This invention relates to peristaltic pumps, and more particularly to safety and use improvements thereto.
A peristaltic pump consists of two principal component parts, the tubing and pumphead assembly. These parts must be mutually compatible in order for the peristaltic pump to be functional. A peristaltic pump is a mechanical pump in which pressure is provided by the movement of a constriction along a tube, as in biological peristalsis. The constriction or pumping action is usually provided by the movement of one or more rollers rotatably mounted on a fixture which in turn rotates on an axis. The movement of the rollers along a segment of the tube within the pump raceway propels fluid through the tubing. There are several interrelated factors that determine the pumping rate including the dimensions and elastic quality of the tubing, as well as the rate of compression applied by the pump rollers. The pump tubing is placed into the raceway and traditionally fixed by means of clamps, flanges or fixtures. Synonyms for peristaltic pump are roller pump, tube pump, and hose pump.
The rate of fluid flow produced by a peristaltic pump is a function of 1) the angular velocity of the roller assembly and 2) the volume of fluid contained within the tubing delimited by constrictions produced by two consecutive rollers. An increase the inside diameter of the pump tubing within the pump raceway will increase the volume of fluid pumped with each cyclic compression of the tubing. Traditional peristaltic roller tubing includes an inlet end, a central pumping segment which interacts with the rollers, and an outlet end. An example of a peristaltic pump used for tumescent infiltration is the Klein Pump (HK Surgical, Inc, US Patent Publication No. 2004/0213685, filed October 2004 to Klein).
The overall functional efficacy of a peristaltic pump system depends on a combination of both the pump's roller assembly and the pump tubing. Pump tubing is at least as important as the pump motor and roller housing in terms of overall performance and reliability.
Tumescent Local Anesthesia (TLA): is a very dilute solution of lidocaine (≦1 gram per liter) and epinephrine (≦1 milligram per liter) with sodium bicarbonate (10 milliequivalents per liter) in a crystalloid solution such as physiologic saline or lactated Ringer's solution. Tumescent liposuction is surgical technique for doing liposuction totally by local anesthesia using tumescent local anesthesia. Tumescent liposuction using TLA is far safer than liposuction performed under general anesthesia. Tumescent or tumescence refers to the state of being swollen and firm. Tumescent liposuction can involve the infiltration of several liters of tumescent local anesthesia into the targeted areas of subcutaneous fat. In addition to large volume liposuction totally by local anesthesia, surgical applications of TLA include a growing list of diverse therapeutic procedures. For example, in patients with symptomatic varicosity of a greater saphenous vein, endovenous laser ablation (EVLA) cannot be safely performed without tumescent local anesthesia infiltrated into the peri-venous compartment of the greater saphenous vein. Because the tumescent fluid acts as a heat sink as well as a local anesthetic, TLA protects nerves and arteries anatomically adjacent to the saphenous vein compartment from heat trauma. TLA is an essential aspect of endovenous laser ablation of the greater saphenous vein. There is a growing list of complex therapeutic (not cosmetic) surgical procedures which are now accomplished totally by local anesthesia using TLA, thereby avoiding the risks of general anesthesia. For example, in elderly patients whose cardiopulmonary status makes them poor candidates for the use of general anesthesia, TLA is now employed for mastectomy totally by local anesthesia (Carlson G W. Total mastectomy under local anesthesia: the tumescent technique. Breast J. 11:100-2, 2005), and arterial surgery for subclavian steal syndrome totally by local anesthesia (Mizukami T, Hamamoto M. Tumescent local anesthesia for a revascularization of a coronary subclavian steal syndrome. Ann Thorac Cardiovasc Surg. 13:352-4, 2007). In all of these clinical applications of TLA surgeons use a peristaltic pump to accomplish the infiltration of tumescent local anesthesia. In order to avoid surgical site infections (SSI) it is essential that the peristaltic tubing be sterile and disposable when used in surgical settings.
Peristaltic pumps typically employ a mechanical system for holding the tube securely in place during roller rotation which consists of several moving parts such as clamps, attachment flanges, connection brackets, or special fixtures that attach to the metal, plastic or glass connectors that join sequentially connected segments of tubing and retain the tubing in a fixed position with respect to the roller assembly housing. Some pump designs employ a clamping mechanism designed to squeeze the tube and hold it in place by virtue of a crimping deformation of the tube. There is need for a simplified roller assembly housing design for securing a peristaltic tube within the roller assembly housing which has no moving parts and only two parts exclusive of the roller assembly, and protects fingers of personnel against injury and protects the roller assembly from damage due to encounters with extraneous or foreign objects.